The sister of a former paratrooper who died in police custody has said police who ordered her to be spied on have "evaded responsibility", after two junior officers were told they had "no case to answer".

Janet Alder was speaking after a four day misconduct hearing for two officers referred to only as Officer One and Officer Two.

Janet Alder was spied on by police (Fiona Hanson/PA)

The two men were accused of gross misconduct over the unauthorised surveillance of Ms Alder more than 17 years ago, outside the inquest at Hull Combined Court into her brother Christopher's death.

On Thursday, a panel of three, sitting in Goole, East Yorkshire, decided there was no case to answer for the two officers.

During the four-day hearing, the panel heard how a police surveillance team was deployed outside the inquest in July 2000 with orders relating to possible public order situations.

The officers facing disciplinary action were accused of carrying out surveillance on July 28 2000 "without appropriate authorisation and justification" when they followed Ms Alder and her barrister, Leslie Thomas QC, and listened to their conversations.

But their lawyers argued they had simply been doing what they were told by more senior officers.

Jason Pitter QC, representing Officer One, told the hearing: "He would have been following instructions given to him by those involved in the wider investigation of the events surrounding the inquest."

He said that although there may have been failings, "the culpability lies with others, further up the chain and parts of the wider system deployed by Humberside Police Service."

The Independent Police Complaints Commission - now the Independent Office for Police Conduct (IOPC) - investigated the surveillance of Ms Alder but the Crown Prosecution Service decided no-one should be prosecuted.

A spokeswoman for Humberside Police said on Thursday: "We complied with the direction from the IOPC to convene a hearing for gross misconduct against the two officers. This hearing has now concluded with a result of 'no case to answer' for both officers."

Detective Chief Superintendent Judi Heaton, of Humberside Police, said: "We know that this has been a distressing time for Ms Alder and her family. We do understand her frustration that the exact details around the case have not been able to be established."

Deborah Coles, director of the campaign group Inquest said: "This hearing amounts to a shocking lack of accountability, as senior officers who authorised this inappropriate and unlawful surveillance evade identification and no one is held responsible.

"This reprehensible spying was a clear attempt to intimidate and undermine Janet's attempts to get to the truth about the brutal reality of the unlawful killing of her brother by police. "